1. Field of the Invention
The present invention relates generally to magnetic sensors and particularly to corrosion protection in a bottom-pinned spin valve sensor.
2. Description of the Related Art
Corrosion in a metal, usually copper, layer of a magnetic read head can be a problem. Corrosion can reduce the effectiveness of magnetic read heads, or even cause a magnetic read head to fail. One method to address this problem is through the use of anisotropic magneto-resistive (AMR) sensors. However, the percentage change in sensor resistance (ΔR/R) for an anisotropic magneto-resistive sensor is only about 2%. The percentage change in sensor resistance is a metric of total signal available from the sensor.
The sensor's ΔR/R can be increased using the giant magneto-resistance (GMR) effect. The ΔR/R for a giant magneto-resistance sensor is about 10% to about 20%. However, a major drawback associated with the giant magneto-resistance sensor is that the giant magneto-resistance sensor re-introduces the problem with corrosion.